The design and music is very reminiscent of old flash games, which is good. I'm glad that the game is the length it is, not too long, not too short. I much enjoyed the determination I felt on trying to beat the more difficult levels.
The mechanics are fun and simple to learn, but I think swapping level 3 and 4 around would give the player a smoother experience learning them.
The only part of the game I didn't enjoy was that I found the shooty gun's random pattern frustrating since I didn't feel like I could strategise for it, I just had to keep trying until I got lucky.
All in all though, a very cool beans game. :o)